JPS6329915Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a centrifugal pump equipped with an impeller having an inducer. Note that in this specification, the term "centrifugal pump" includes not only so-called centrifugal pumps for liquids, but also centrifugal compressors and centrifugal blowers for gases.

[Prior art]

A centrifugal compressor is shown as a conventional example of this type of machine. Figure 1 shows the open type, with impeller 1
The blade 2 is provided with only the main plate 3. 4 is a casing. FIG. 2 shows one equipped with a side plate 5, and 6 is a liner ring.

[Problem that the invention attempts to solve]

In such conventional devices, it is difficult to control the boundary layer that develops inside the blade 2, particularly in the large radius portion near the inlet, and has the disadvantage of reducing efficiency.

The object of the present invention is to eliminate the above-mentioned drawbacks of the conventional turbomachine, suppress the development of a boundary layer, and provide an efficient centrifugal turbomachine.

[Means for solving problems]

The present invention provides a centrifugal pump having an inducer connected to the impeller at the inlet of the impeller. A gap is provided between the inner circumferential surface of the outer casing into which the ring is fitted and the outer circumferential surface of the communication ring, and a plurality of passages are opened to communicate with the outer circumference of the throat portion from the gap, and a plurality of passages are connected to the inducer from the gap. This centrifugal pump is characterized in that a plurality of passages that communicate with and open to an inlet portion are provided distributed over the entire circumference.

[Effect]

In the present invention, the outer periphery of the throat part (the part of the inlet of the blade where the distance between adjacent blades is the narrowest) and the inlet part of the inducer are communicated over the entire circumference, so the inlet of the inducer The boundary layer, which has been gradually growing toward the back, is sucked up and eliminated by the throat portion, and the boundary layer is prevented from growing even larger, so that efficiency can be improved.

〔Example〕

An embodiment of the present invention will be described with reference to the drawings regarding a centrifugal compressor.

In FIG. 3, 7 is an inducer extending continuously from the blade 2, 8 is an inlet portion of the inducer 7, and 9 is a throat portion. A communication ring 10 is placed on the outside of the inducer 7 and inside the casing 4.
is attached removably. The communication ring 10 is provided with a groove 11 as a gap around the circumference on its outer circumferential surface facing the casing 4, and is further provided with a communication opening on the outer circumference of the throat portion 9 so as to communicate with the groove 11 from the inner circumference. A passage 12 is opened to communicate with the inlet part 8, and passages 13 are provided distributed over the entire circumference as shown in FIG. ing.

The effect will be explained. In general, the relative velocity distribution near the side plate of an impeller with an inducer is as shown in FIG. 5, where it rapidly decelerates immediately after the entrance of the inducer, reaches its lowest at the throat, and the pressure increases in this region.

In the embodiment described above, the passages 12 and 13 and the groove 11 form a communication passage, so that part of the fluid in the large radius portion of the blade of the throat portion 9, which is under high pressure, is diverted from the passage 12. It is sucked up and returned from the passage 13 through the communication passage to the inlet section 8 where the pressure is low. This flow absorbs the boundary layer generated near the throat portion 9, suppressing the growth of the boundary layer, and improving efficiency.

FIG. 6 shows an example in which the impeller 1 is of an open type, and has similar effects.

[Effect of idea]

With this invention, it is possible to absorb and remove the boundary layer that forms on the blade, suppress the growth of the boundary layer, and improve efficiency.Furthermore, the structure is extremely simple because the communication path is provided in a removable communication ring. It is possible to provide a certain centrifugal pump, which can have extremely great practical effects.

[Brief explanation of drawings]

Figures 1 and 2 are longitudinal sectional views of the conventional example, Figure 3 is a longitudinal sectional view of the embodiment of the present invention, and Figure 4 is the A-A
5 is a diagram showing the relative velocity on the side plate, and FIG. 6 is a longitudinal sectional view of another embodiment of the present invention. 1... impeller, 2... impeller, 3... main plate, 4...
...Casing, 5...Side plate, 6...Liner ring, 7...Inducer, 8...Inlet section, 9...
Throat part, 10... Communication ring, 11... Groove,
12, 13...Aisle.

Claims (1)

[Scope of utility model registration request] In a centrifugal pump having an inducer connected to the impeller at an inlet of the impeller, a communication ring is removably provided on an outer casing of the inducer between the inlet and throat of the inducer, and the communication ring is fitted. A gap is provided between the inner circumferential surface of the outer casing and the outer circumferential surface of the communication ring, and a plurality of passages are opened and communicated from the gap to the outer circumference of the throat portion, and a plurality of passages are communicated from the gap to the inducer inlet. A centrifugal pump characterized by having a plurality of open passages distributed over the entire circumference.